export function isPrimaryPointer(event: PointerEvent) {
  if (event.pointerType === 'mouse') {
    return typeof event.button !== 'number' || event.button <= 0
  }
  else {
    /**
     * isPrimary is true for all mice buttons, whereas every touch point
     * is regarded as its own input. So subsequent concurrent touch points
     * will be false.
     *
     * Specifically match against false here as incomplete versions of
     * PointerEvents in very old browser might have it set as undefined.
     */
    return event.isPrimary !== false
  }
}
